Softgel capsules are nowadays usually produced by the rotary die method, which was described for the first time in U.S. Pat. No. 2,288,327. In this method, two bands of film, for example of aqueous gelatin solution, are guided over counter-rotating forming rolls and fused to each other. On their surface, these forming rolls have recesses (cavities), which are encircled by flanges. The two bands are suitably heated to below the melting point and fused to each other under the force of the flanges. At the same time, shaped articles in the form of soft capsules are severed from the bands by being pinched off. During the fusing of the bands, the capsules thereby forming are dosed with filling material through fine channels in the filling wedge.
The dosing of the filling material is performed with the aid of precision dosing pumps (piston-type dosing pumps), which are in the same generic category as reciprocating displacement machines. The metered volume of fluid is thereby brought up to the capsule halves on both sides through the filling wedge in a number of pulses, depending on the size of the volume by way of individual lines for each capsule of 30 to 70 cm in length. In this case, both the principle of half-dosing into each of the two capsule halves (Y-shaped duct) and single-channel conductance (I-shaped duct) up to the tip of the filling wedge (buttonhole segment) are customary. The capsules created are in this case made to bulge to the extent to which a pumping surge forces filling material into the capsule cups. Although the principle was described as long ago as 1935, the design of the pumps and of the filling wedge has remained substantially unchanged to the present day and is still in use.
Soft gel capsules are generally made by a using an apparatus as illustrated in FIGS. 1-3.
The manufacturing apparatus shown in FIG. 1 includes a pair of die rolls 1, 1 that are close to and confront each other, a nozzle segment 2 that supplies a filling material and is formed of an inverse mountain-like projection 3 having curved faces that are positioned in confronting relation with each other at right and left sides about the lower end central portion thereof, wherein the projection 3 confront and is engaged in a curved recess 4 that is formed by surrounding curved peripheral surfaces of the die rolls 1, 1 at the upper sides thereof, and a supply hopper 5 located at the uppermost end thereof.
There are a distributor (dispersion plate) 6 for distributing the filling material, a slide valve mechanism 7 for controlling the supply of the filling material by sliding operation, a tube assembly plate 8 on which pipes for connection with a plurality of tubes are provided upright, and a plunger type pump 9 (hereinafter referred to simply as a pump 9) having a plurality of cylinders, that are respectively interposed between the nozzle segment 2 and the supply hopper 5 in the ascending order, and wherein the plurality of tubes (hoses) 10 for supplying the filling material therethrough that are provided between the plurality of cylinders of the pump 9 and the tube assembly plate 8. Further, there are provided a return tube (hose) 11 that is interposed between the distributor 6, the slide valve mechanism 7 and the supply hopper 5, for returning the filling material that becomes useless, strip rolls 12, 12 for separating a pair of soft capsules that are provided under and appropriately away from the die rolls 1, 1, and a pair of mangle rolls 13, 13 which draws the pair of gelatin sheets.
When manufacturing the soft capsules, two gelatin sheets 14, 14 are supplied between the pair of rotating die rolls 1, 1 from the upper side thereof at the right and left sides thereof, and the filling material such as liquid medicine is filled in the supply hopper 5, wherein the filling material is supplied to a plurality of nozzle holes 15 that are arranged in one row in a longitudinal direction of the right and left curved faces of the inverse mountain-like projection 3 of the nozzle segment 2 at portions close to the lower end edge (or at the lowermost end edge) through the tubes 10, the tube assembly plate 8, the slide valve mechanism 7 and the distributor 6 when the pump 9 is actuated.
As a result, a plurality of capsule pockets 16 that are provided on the outer peripheral surfaces of the die rolls 1, 1 and arranged axially in a row occupy the nozzle holes 15 of the nozzle segment 2 while they are rotated, and hence the filling material is temporarily stored inside two gelatin sheets 14, 14, and they are conveyed downward with the rotation of the die rolls 1, 1. The gelatin sheets 14, 14 are brought into intimate contact with each other in a moment when the filling material passed through the narrowest part between the die rolls 1, 1, and they are cut and brought into intimate contact with each other under pressure at the same time when the annular blades that are formed at the peripheries of the capsule pockets 16 of the die rolls 1, 1 mesh with each other, so that intended soft capsules 17 are formed.
The thus formed soft capsules 17 that remain stuck to the capsule pockets 16 of the die rolls 1, 1 are stripped off by a brush or the like while the soft capsules 17 that remain stuck to a remaining gelatin sheet 18 formed by bonding two gelatin sheets 14, 14 are separated by the pair of strip rolls 12, 12, and also the remaining gelatin sheet 18 is drawn downward by the pair of mangle rolls 13, 13.
The soft capsules are instantaneously manufactured in practice, wherein the setting of the discharging accuracy of the filling material from the nozzle holes 15 of the nozzle segment 2 and of the timing such as rotation of the die rolls 1, 1 become very important. If the discharging accuracy and the timing such as rotation are poorly set, the amount of the filling material filled in the soft capsules 17 is varied or the gelatin sheets 14, 14 are poorly bonded to each other or there occurs the deformation of the shape of the soft capsules 17.
Accordingly, there has been generally employed a pump as the pump 9 shown in FIG. 2, wherein the pump includes a plurality of cylinders 18a, 18b (respectively five cylinders in this example) that are arranged symmetrically at right and left. Either of the cylinders 18a, 18b corresponds to each nozzle hole 15 of the nozzle segment 2 so as to secure the discharging accuracy, and a timing between the actuating or driving speed of the pump 9 and the rotational speed of the die rolls 1, 1 is accurately provided or set using a timing gear or the like.
For example, a filling state is explained with reference to a case using the pump or plunger 9 shown in FIG. 2, the typical nozzle segment 2 having five nozzle holes 15a to 15e as shown in FIGS. 3a and 3b, and a typical right die roll 1 (left die roll 1 is omitted having three capsule pockets 16a, 16b and 16c that are arranged along the row denoted by the line A-A and two capsule pockets 16a and 16b are arranged along the row denoted by the line B-B wherein these capsule pockets are repeatedly provided in the circumferential direction.
When the filling material is filled in the three capsule pockets 16a, 16b and 16c that are arranged in the row denoted by the line A-A, all the cylinders 18b provided at the right side of the pump 9 are actuated, while when the filling material is discharged, the nozzle holes 15a, 15c and 15e of the nozzle segment 2 corresponding to the capsule pockets 16a, 16b and 16c are used, whereas the filling material corresponding to the nozzle holes 15b and 15d is returned to the supply hopper 5 through the distributor 6, the slide valve mechanism 7 and the return tube 11.
Meanwhile, when the filling material is filled in the next two capsule pockets 16a and 16b that are arranged in the row denoted by the line B-B, all the cylinders 18b provided at the right side of the pump 9 are actuated, while when the filing material is discharged, the nozzle holes 15b and 15d of the nozzle segment 2 corresponding to the two capsule pockets 16a and 16b are used, whereas the filling material corresponding to the nozzle holes 15a, 15c and 15e are returned to the supply hopper 5 through the distributor 6, the slide valve mechanism 7 and the return tube 11. Such a filling operation is simultaneously operated at the left side of the die roll 1.
Such a discharging process is sequentially repeated by the rotation of the die rolls 1, 1 so as to form intended soft capsules 17. (Angres)
There is a long felt need in the art for filling softgel capsules more efficiently and more accurately.